Serum total thyroxine concentration

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114.

experimental_model

Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12

exposure

One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized.

limitations

Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. The 40% figure is a within-treatment change described in the abstract, not a verified adjusted between-group estimate.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Iodine repletion restored thyroid hormone status in these moderately deficient children.

primary_references

[iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

tissue_or_cell_type

Thyroid hormones and cognitive/motor testing

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1300–1312

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 · source_derived_draft · unverified_draft

### iod-clin-albania-thyroxine At 24 weeks, mean total T4 in iodine-treated children was approximately 40% higher than baseline and hypothyroxinemia prevalence was below 1%; corresponding placebo-group status did not improve significantly. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Iodine repletion restored thyroid hormone status in these moderately deficient children. organism: Homo sapiens tissue_or_cell_type: Thyroid hormones and cognitive/motor testing experimental_model: Randomized double-blind placebo-controlled 24-week trial in 310 moderately iodine-deficient Albanian children aged 10–12 limitations: Baseline groups differed on four psychological tests; analyses adjusted for baseline score, school and sex. Follow-up was 24 weeks, with no proof of lasting IQ or school-performance improvement. Symbol-search test-retest reliability was modest. Dose is a historical depot intervention, not daily intake. The 40% figure is a within-treatment change described in the abstract, not a verified adjusted between-group estimate. exposure: One supervised oral dose of iodized poppyseed oil containing 400 mg iodine versus sunflower-oil placebo; baseline median urinary iodine 43 micrograms/L, 87% goitrous; iodine 159/placebo 151 randomized. cross_nutrient: false evidence_location: Primary full PDF Methods, Results, Tables 1–2 and Discussion, pp.108–114. [iod-clin-albania2006] Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. (2006). https://pubmed.ncbi.nlm.nih.gov/16400058/ DOI: 10.1093/ajcn/83.1.108

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence

exposure

Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements.

limitations

Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials. The abstract does not provide the exact between-group thyroxine effect size. The two iron trials have distinct populations and endpoints; their hormone results are not declared a contradiction.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

This iron–iodine trial also found a hormone response.

primary_references

[iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747

tissue_or_cell_type

Thyroid volume, circulating thyroxine and iron indices

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1244–1256

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence · source_derived_draft · unverified_draft

### iod-clin-dual-salt-thyroxine Serum thyroxine was higher with dual-fortified salt than with iodized salt alone (P<0.05), with lower reported hypothyroidism and goiter prevalence (P<0.01). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: This iron–iodine trial also found a hormone response. organism: Homo sapiens tissue_or_cell_type: Thyroid volume, circulating thyroxine and iron indices experimental_model: Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence limitations: Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials. The abstract does not provide the exact between-group thyroxine effect size. The two iron trials have distinct populations and endpoints; their hormone results are not declared a contradiction. exposure: Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Randomized double-blind placebo-controlled trial in 166 goitrous iron-deficient children aged 5–14 in Côte d’Ivoire

exposure

All consumed iodized salt providing 10–30 mg iodine/kg salt at household level; iron group received 60 mg elemental Fe/day, four days/week for 16 weeks; outcomes followed to 20 weeks.

limitations

This tests iron treatment on a background of iodine supply. It does not directly measure TPO activity or prove that iron deficiency always prevents iodine response. Specific iron-supplement salt not verified from abstract. The whole-blood thyrotropin assay is identified explicitly; it is not claimed to be the same specimen matrix as serum TSH.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Improved thyroid size did not mean every hormone measurement changed.

primary_references

[iod-clin-hess2002] Treatment of iron deficiency in goitrous children improves the efficacy of iodized salt in Côte d'Ivoire. (2002). https://pubmed.ncbi.nlm.nih.gov/11916762/ DOI: 10.1093/ajcn/75.4.743

tissue_or_cell_type

Thyroid ultrasound and blood thyroid indices

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1216–1228

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized double-blind placebo-controlled trial in 166 goitrous iron-deficient children aged 5–14 in Côte d’Ivoire · source_derived_draft · unverified_draft

### iod-clin-iron-salt-hormone-null The iron and placebo groups showed no significant difference in serum thyroxine or whole-blood thyrotropin at baseline or during the intervention. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Improved thyroid size did not mean every hormone measurement changed. organism: Homo sapiens tissue_or_cell_type: Thyroid ultrasound and blood thyroid indices experimental_model: Randomized double-blind placebo-controlled trial in 166 goitrous iron-deficient children aged 5–14 in Côte d’Ivoire limitations: This tests iron treatment on a background of iodine supply. It does not directly measure TPO activity or prove that iron deficiency always prevents iodine response. Specific iron-supplement salt not verified from abstract. The whole-blood thyrotropin assay is identified explicitly; it is not claimed to be the same specimen matrix as serum TSH. exposure: All consumed iodized salt providing 10–30 mg iodine/kg salt at household level; iron group received 60 mg elemental Fe/day, four days/week for 16 weeks; outcomes followed to 20 weeks. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-hess2002] Treatment of iron deficiency in goitrous children improves the efficacy of iodized salt in Côte d'Ivoire. (2002). https://pubmed.ncbi.nlm.nih.gov/11916762/ DOI: 10.1093/ajcn/75.4.743

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

true

evidence_location

Primary indexed abstract.

experimental_model

Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire

exposure

Selenium 50 micrograms/day as selenomethionine or placebo for two months; no concurrent iodine-repletion regimen reported in the abstract.

limitations

The abstract reports before/after changes in the selenium group; do not mistake these for adjusted between-group estimates. DIO1 restoration was a proposed explanation, not directly measured. Hormone changes do not themselves establish symptomatic deterioration or a universal order for supplement treatment.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

Selenium alone lowered circulating T4 in this co-deficient population.

primary_references

[iod-clin-contempre1992] Effect of selenium supplementation on thyroid hormone metabolism in an iodine and selenium deficient population. (1992). https://pubmed.ncbi.nlm.nih.gov/1424183/ DOI: 10.1111/j.1365-2265.1992.tb02268.x

tissue_or_cell_type

Serum thyroid-hormone concentrations

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1258–1270

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire · source_derived_draft · unverified_draft

### iod-clin-selenium-total-t4 Mean serum total T4 fell from 73.1 ± 45.4 to 48.3 ± 23.7 nmol/L after two months of selenium treatment (P<0.001) in the iodine/selenium-deficient setting. Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Selenium alone lowered circulating T4 in this co-deficient population. organism: Homo sapiens tissue_or_cell_type: Serum thyroid-hormone concentrations experimental_model: Placebo-controlled selenium intervention in 52 schoolchildren from a region of severe iodine and selenium deficiency in northern Zaire limitations: The abstract reports before/after changes in the selenium group; do not mistake these for adjusted between-group estimates. DIO1 restoration was a proposed explanation, not directly measured. Hormone changes do not themselves establish symptomatic deterioration or a universal order for supplement treatment. exposure: Selenium 50 micrograms/day as selenomethionine or placebo for two months; no concurrent iodine-repletion regimen reported in the abstract. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-contempre1992] Effect of selenium supplementation on thyroid hormone metabolism in an iodine and selenium deficient population. (1992). https://pubmed.ncbi.nlm.nih.gov/1424183/ DOI: 10.1111/j.1365-2265.1992.tb02268.x

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

false

evidence_location

Primary PDF Methods, trial profile, Results and Table2, pp.197–209.

experimental_model

Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions

exposure

Term infants ≤ 8 weeks; indirect arm 121 pairs: mother 400 mg iodine as oral iodized poppyseed oil, infant placebo; direct arm 118 pairs: infant about 100 mg iodine from half a 200 mg oil capsule, mother placebo; follow-up 3, 6, 9 months.

limitations

Both arms received active iodine somewhere in the pair; there was no wholly untreated arm. Breastfeeding and baseline deficiency contextualize the result; measured iodine status is not a child cognitive outcome. Actual infant study dose was about 100 mg, not the 200 mg guideline discussed elsewhere in the paper. No serious adverse events were reported; this does not establish safety for other infant doses, preparations or settings.

nutrient_topic

Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine

organism

Homo sapiens

plain_language

A categorical thyroid outcome improved even though average hormone comparisons were not significant.

primary_references

[iod-clin-bouhouch2014] Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. (2014). https://pubmed.ncbi.nlm.nih.gov/24622750/ DOI: 10.1016/s2213-8587(13)70155-4

tissue_or_cell_type

Breast milk, infant urine and thyroid function

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1566–1578

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions · source_derived_draft · unverified_draft

### iod-clin-lactation-hypofunction Infant thyroid hypofunction classifications were less frequent with indirect maternal supplementation (P=0.023), although infant TSH and T4 concentrations did not differ significantly between groups over time (P=0.597 and 0.184). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: A categorical thyroid outcome improved even though average hormone comparisons were not significant. organism: Homo sapiens tissue_or_cell_type: Breast milk, infant urine and thyroid function experimental_model: Double-blind randomized trial in Morocco;241 mother–infant pairs enrolled, 239 randomized after two age exclusions limitations: Both arms received active iodine somewhere in the pair; there was no wholly untreated arm. Breastfeeding and baseline deficiency contextualize the result; measured iodine status is not a child cognitive outcome. Actual infant study dose was about 100 mg, not the 200 mg guideline discussed elsewhere in the paper. No serious adverse events were reported; this does not establish safety for other infant doses, preparations or settings. exposure: Term infants ≤ 8 weeks; indirect arm 121 pairs: mother 400 mg iodine as oral iodized poppyseed oil, infant placebo; direct arm 118 pairs: infant about 100 mg iodine from half a 200 mg oil capsule, mother placebo; follow-up 3, 6, 9 months. cross_nutrient: false evidence_location: Primary PDF Methods, trial profile, Results and Table2, pp.197–209. [iod-clin-bouhouch2014] Direct iodine supplementation of infants versus supplementation of their breastfeeding mothers: a double-blind, randomised, placebo-controlled trial. (2014). https://pubmed.ncbi.nlm.nih.gov/24622750/ DOI: 10.1016/s2213-8587(13)70155-4